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Chapter 4 INPUT AND OUTPUT OBJECTS

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Presentation on theme: "Chapter 4 INPUT AND OUTPUT OBJECTS"— Presentation transcript:

1 Chapter 4 INPUT AND OUTPUT OBJECTS

2 Chapter 4 The cout Object The cout object is used to display information to the monitor and is contained in the iostream.h and iostream header files.

3 Chapter 4 Using the cout Object cout << item #1 << item #2 << item #3 << ·· << item #n;

4 Chapter 4 The cout Output Stream Flows to the System Monitor

5 Chapter 4 Using \n and endl

6 The C++ Escape Sequences Used with cout
Chapter 4 The C++ Escape Sequences Used with cout \a Beep \b Backspace \n CRLF \r CR \t Horizontal tab \v Vertical tab \\ Backslash \' Single quote \” Double quote \? Question mark

7 Chapter 4 I/O Stream Manipulators setw(n) Sets field width to n setprecision(n) Sets floating-point precision to n setfill(n) Sets fill character to n ws Extracts white space characters endl Inserts a new line in the output stream, then flush Flushes the output stream

8 Chapter 4 Setting the Field Width cout << setw(field width) << output item;

9 Chapter 4 Generating Decimal Point Values cout.setf(ios::fixed ); cout.precision(n);

10 Chapter 4 Generating Left-Justified Values cout.setf(ios::fixed); cout.setf( ios::left);

11 Chapter 4 Generating Currency Values cout.setf(ios::fixed); cout.setf(ios::showpoint); cout.precision(2);

12 Formatting Functions and Flags setf() Sets a formatting flag.
Chapter 4 Formatting Functions and Flags setf() Sets a formatting flag. unsetf() Unsets a formatting flag. precision(n) Sets decimal output to n decimal places. fixed Forces fixed decimal point output. left Forces left justification within field. right Forces right justification within field. scientific Forces exponential, e, output. showpoint Forces a decimal point to be displayed along with trailing 0’s.(Used for currency outputs) showpos Forces a + sign output for positive values.

13 Chapter 4 The cin Object The cin object is used to read information from the keyboard and is contained in the iostream.h and iostream header files.

14 Chapter 4 The cin Input Stream Flows from the Keyboard

15 Using the cin Object cin >> variable to be read;
Chapter 4 Using the cin Object cin >> variable to be read; Only one character is read at a time. White space (blanks, tabs, new lines, carriage returns, etc.) are ignored by cin when using the >> operator. However, white space can be read using different cin functions. Numeric values can be read as characters, but each digit is read as a separate character.

16 Chapter 4 Using get() and put() For Single Character Data cin.get(character variable); cout.put(character variable);

17 Chapter 4 Reading Strings Using getline() getline(input stream, string object, 'delimiting character’); To avoid a potential problem, use the line cin >> ws before the cin.getline() statement.

18 Chapter 4 Opening an Input File ifstream fin(”file path"); Opening an Output File ofstream fout(”file path"); Opening an Input/Output File fstream finout(“file path”);

19 Processing an Open File if(!fileObject)
Chapter 4 Processing an Open File if(!fileObject) { cout << "This file cannot be opened" << endl; exit(1); }//END IF else while (Read Data Item From Input File ) { //BEGIN LOOP Process data item. } //END LOOP }//END ELSE


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